1. Field of the Invention
This invention relates to a method for producing a decorative design laminate. More particularly, it relates to a novel method for producing a decorative design laminate from a computer generated image or design, transferring such image from a carrier to a substrate utilizing an embossing resin. Even more particularly, the novel method of the present invention relates to decorative design laminates for application to substrates suitable for aircraft interior panels.
2. Description of Prior Art
In the prior art, the most commonly used printing process known for aircraft applications, specifically for aircraft interior decorative laminates, is silk-screening. Unfortunately, silk-screening has a variety of inherent disadvantages. For instance, alterations of a design are difficult, costly, and time intensive, since each alteration, even the most minute, requires the creation of entirely new sets of screens. Each color alteration normally requires employing the costly and lengthy process of (1) color mixing and matching, (2) creating complete "laboratory" samples, and (3) creating the full-size production design. The full-size production design must be consistent with the laboratory sample. Multi-colored screens are even more expensive and time-consuming, regardless of whether "spot-color" silk-screening is used or four-color process silk-screening. Like other forms of prior art, silk screening is most economical, absorbing set-up costs, when large quantities are run, but such large "runs" often compromise color consistency. Moreover, in the aircraft decorative interior market, large quantities of a single design are relatively rare.
Other known processes which are used to decorate laminates for aircraft interior products include gravure printing, the use of integrally colored materials such as ABS (a type of vinyl), or the use of a solid color film laminated to a substrate. The inherent disadvantages of these processes are that they (1) limit the design to virtually one or two colors, (2) they limit customization of the design which often identifies the airline, and (3) they are most effectively produced in large quantities small "runs" being expensive and essentially cost prohibitive.
Various prior art methods exist for inclusion of digitally produced images in laminates, but non are suitable for aircraft laminates. One such prior art method is known as the "wet-method." An image is digitally created and printed electrostatically onto a transfer medium using heat and pressure. The image is mirrored, introducing the possibility for error. The image is then immersed in water, and using pressure, applied to a second film, from which the transfer medium is stripped.
U.S. Pat. No. 3,350,254 to Morgan et al. discloses a wet method utilizing a mixture of oil, resin and an elastomer. An exposed water soluble surface of the paper is washed away by wetting. In U.S. Pat. No. 3,350,254, a clay is used on the water soluble surface. Thereafter, the printed image remains adhered to the layer formed by the mixture. The transferred image is washed and dried. A protective laminate, such as transparent vinyl, having an adhesive side is often applied over the image to form a protective layer. The limitations with this method are: (a) there are additional steps (i.e., the wet transfer itself), drying time, and (b) this method is not generally amenable with materials used in aircraft interior decorative laminates that conform to government regulations of aircraft performance standards. This method is also considered messy and laborious.
In an effort to improve image transfer processes, a "dry" method was discovered eliminating many of the messy and laborious disadvantages of the "wet" method. This dry method uses heat and/or pressure to transfer an image printed on transfer paper to a chosen substrate. The transferred image is then overlaid with a protective film and secured with an adhesive. In this type of "dry" method a mirrored or negative image may have to be printed on the transfer paper. Such is shown in U.S. Pat. No. 3,013,917 to Karlan, et al. Such dry methods also have inherent disadvantages. For instance, they are considered slow and unreliable. If parts of the image do not transfer, the total image is ruined. High rejection rate causes extensive material waste, increased production cost, and waste of human resources. The particular overlay materials in typical aircraft products such as Tedlar are especially difficult to use with the "dry" transfer method since Tedlar will not readily accept the image.
In an effort to improve the "dry" transfer method, it was discovered that a pressure-sensitive adhesive-coated film could be used to lift the image from the transfer paper and thereafter secured to a final substrate. Such is shown in U.S. Pat. No. 4,983,487 to Gilreath wherein the adhesive coated film is shown to be the transfer medium. Unfortunately, the Gilreath invention also has many inherent disadvantages. One disadvantage is that the adhesive-coated film, used as the transfer medium, must be highly transparent so that the image may be viewed when applied to the final substrate. Use of a non-transparent film to capture the image would frustrate the purpose of the invention in that the image would not be viewable once it is applied to the final substrate. A second disadvantage is that textures can not be introduced. Since nowhere in Gilreath does the invention contemplate the use of an embossing resin, the laminate would not have the texture retention capabilities necessary for aircraft products. A third disadvantage is that Gilreath may have to be practiced utilizing a mirrored image. Use of such mirrored images provides for possible transfer error. Fourth, the Gilreath invention would most likely not meet many of the strict government regulations or aircraft performance standards due to the use of standard adhesives which can be highly flammable. Finally, Gilreath does not contemplate the use of an inkjet or airbrushed produced image. Therefore, the Gilreath invention is limited in its application to electrostatically produced images.
An improved "dry" method for creating design laminates is needed which can overcome the many disadvantages of the prior art. Such method should be able to meet the strict government and aircraft performance standards so that such design laminate can be used in aircraft interiors.